Biological evolution vs. word games
Each generation tends to resemble the previous one, so evolution of whales from land animals, for example, took many generations. One limitation on the power of natural selection is that each generation must be viable. Some creationist suggested that the problem is analogous to "evolving" a sentence one letter at a time to make a substantially different sentence, while requiring that each intermediate step be a valid sentence. The Mosquito Eater has solved this challenge. Cool!
But we no longer need to rely on imperfect analogies to biological evolution. Molecular tools now make it possible to explore multistep evolution experimentally, as I discussed in an early post.